This research will help to fill a major gap in U.S. demographic history. The project will analyze a Public Use Sample drawn from manuscript records of the 1910 U.S. Census of Population. This Census asked questions on cumulative numbers of children ever born and surviving. Data resulting from the latter question were never published. These questions will be the basis of an analysis of levels, trends, and differentials in child mortality. Fertility analysis will rely heavily on these questions combined with data on the number and ages of own-children in a woman's household. The quality of the Census data will be carefully evaluated and estimates of fertility and child mortality will be prepared for the U.S. population as a whole and for major social groups. Limited coverage of the death registration area and the complete absence of a birth registration area during the first decade of the twentieth century enhances the value of these fertility and mortality estimates. In the course of making these estimates, a data file will be prepared that will link women with their husbands and own children. This file will be distributed as an additional public use file. In addition to forming the basis of aggregate demographic estimates, the file will be used to test specific hypotheses about the determinants of fertility and child mortality. These include hypotheses about the spread of knowledge of proper child care practices and of urban public health services; the effect of land availability on farm fertility; the role of compulsory school legislation in reducing fertility; and the relative importance of social structural and cultural variables in the adoption of family limitation.